Headlight



W. G. WOOD.

HEADLIGHT.

APPLICATION ,FILED AUG-15, 1918.

Patented Dec. 21, 1920.

Inzenior Willim G. "60d a. troop, or

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X or we t l7? a in l tart 1L,3E3,@'?f3 specification oi ll-ottersPatent.

Application filed nue ust serial 1%.

To all whom it may concern Be it known that l, WILUAM Ween, a citizen ofthe United States, residing at Berkeley, in the county of Alameda andState of -California, have invented new and useful improvements inHeadlights, of which the following is a specification.

This invention relates to headlights such as are employed onautomobiles, locomotives and the like, and particularly to improvernenmon the structure shown in my co-pending application entitled,liteadlight, filed au ust 5, 1918, Serial No. 2%,303.

In the present invention, 1 provide a lamp which, following generallythe principles of the lamps disclosed in the above mentionedapplication, employs a reduced light ereitting aperture through which acone-shaped beam of sharp outline is projected. When the observer is notdirectly in the path of the beam, the only point of illumination on sucha lamp is the small lens which fits in the reduced light emittingaperture. This lens can be seen from various points of angularityforwardly of the lamp. lo the present case, I extend a hood out over thelight emitting aperture, said hood serving; to conceal the lens at alltimes except when the observer is directly in the path of the beam.lhus, for all practical purposes, 1 ani enabled by the employment ofthis hood to provide a lamp capable of projecting a suitable beam ofgreat intensity and wherein the source of the light is effectivelyconcealed. In the case of an automobile headlight, the uppermost rays ofthe cone-shaped beam are kept below a horizontal line, and hence nothingis illuminated but the ground some'distance ahead.

One form which my invention may assume is exemplified. in thefollowing'description and illustrated in the accompanying draw ing, inwhich Figure 1 is a central, vertical, longitudinal section through theheadlight, or 'what might be termed a side elevation in section.

Fig". 2 is a front view of the same.

Referring to the drawings in detail, A indicates in general theheadlight casing. By referring to the drawings it will be. seen that itis oblong and circular in shape, and that it consists of two sectionssuch as shown at 2 and 3, said sections being secured toportion of thecasing section ll at 5 is a I transparent window or aperture, which ismounted a condensing lens '8 of the piano- .convex type, said lens beingsecured in a screw cap 7, or any other suitable means to a permit it tobe readily removed lfor or otherfpurposes.

Mounted-in the rear portion of the casing; is a parabolic reflector 8and secured in soclret 9 within the reflector is an electric bulb l0 ofthe usual construction. This bulb is preferably adjustablelongitudinally to permit a perfect focusing of with relation. to theparabolic reflector.

Secured in any suitable manner of the parabolic reflector is condsnsilens ll. and interposed between said. the opening 5 is a plurality ofannular plates 12. These are provided central openings as shown at 13throu h which the light rays to projected pass. The openings 13 in therespective de" crease in size as they a preach the aperture 5, thisbeing due to the fact the rays condensed by the lens ll assume the formof a cone-shaped beam which has its focal point approximately inaperture 5. Secured to the cap 7, or, if desired, to the casing 2, is ashield llhis shield is coneshaped to conform with the light beam prosjected through the aperture 5, or the lens ll, its lower side ispreferably cutaway as shown at 15.

By referring to Fig. 1 it can readily be seen that if the bulb 10 isproperly focussed a beam of substantially parallel rays will beprojected against the lens 11 by the para 'bolic reflector. The raysreceived by the lens from the reflector when passing through the sarneare condensed or converged, and are thus brought to a focal point in theaperture 5. They will at the saine time spread or diverge after passingthrough said aperture,

and it can, therefore, be seen that a cone shaped beam is projected, dueto the fact that a condensing lens of the plane-convex type is interosed between the parabolic redoctor and t e transparent aperture. Thebeam projected through the aperture has the appearance of a cone-shapedbeam with the apex of the cone at the aperture, and the Mill aperturethrough which it is projected is,

practically speaking, invisible, due to the fact that the rays arebrought to a focal point in the aperture, and also due to the ills factthat a surrounding shield 14 is employed. It is, therefore, impossiblefor an observer stationed ahead of the headlight, particularly on eitherside thereof, to see any visible source of light, except when enteringthe beam of light projected. This is of great importance when driving anautomobile, as the objectionable glare generally produced by headlightsis, in this instance, entirely eliminated, due to the fact that no raysare projected above the horizontal line shown at 16. All stray rayscaused by imperfections in the reflector 8 or the condensing lens 11 areretained within the headlight, due to the fact that they will eitherstrike the interior surface or the baffle rings 12;

While a specific form of lens is interposed between the transparentaperture and the parabolic reflector 8, I wish it understood that anyother form of lens or means capable of the same function, may beemployed.

Similarly, that the materials and finish of the several parts formingthe headlight may be such as the experience and judgment of themanufacturer may dictate.

Important factors to the successful projection of a concealed source oflight are (a) employment of a reduced light emitting aperture; (6)projection of a sharply defined cone-shaped beam therethrough; and (0) ahood of about the same divergence as the rays of the beam so that thelight rays are not obstructed, such hood being extended far enough aheadto conceal the lens in the light emitting aperture when the observer isout of the direct path of the beam of light. If the hood obstructs thelight rays, its interior will thereby be illuminated and also a fringewill be formed around its ed e which will be plainly visible to one stanin outside of the path of the beam.

illaving thus described my invention, what I claim and desire to secureby Letters Patent is:

1. In a lamp, a casing having a reduced light emitting aperture,-asource of light in the casing, means for projecting a coneshaped beamthrough the reduced aperture, and a hood on the casing surrounding thelight emitting aperture but out of interference with the projected beam,said hood being extended far enough ahead to conceal the light emittingaperture from view when observed from any point not in the direct pathof the projected beam.

2. A headlight comprising a casing having a small transparent apertureformed therein, a source of light in the casing, means cooperating withsaid light, adapted to project a cone-shaped beam through thetransparent aperture, said beam having a focal point in the aperture atwhich the light rays of the beam cross, a lens in the aperture, a bafliering within the casin positioned adjacent the focal point of the beam,said ring having a central opening formed therein which is sli htly lessin diameter than the cone-shaped beam projected therethrough, and ashield exterior of the casing partly surrounding the,transparentapertures through which the cone-shaped beam is projecte 3. A headlightcomprising a casing having a transparent aperture formed therein, asource of light in the casing, a parabolic reflector surrounding saidlight, means interposed between the reflector and the transparentaperture adapted to concentrate and converge the reflected rays from thepara:

bolic reflector to a common focal point before they are projectedthrough the transparent aperture, and means for rendering thetransparent aperture invisible to an observer stationed in front of theheadlight,

except when standing directly in the beam projected.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses. g

Y WILLIAM G. WOOD.

Witnesses:

JOHN H. HERRING, W. W. HEALEY,

